Plastic cap



Nov. 22, 1966" J. A. MOINTOSH 3,286,866

PLASTIC GAP Filed April 15, 1965 INVENTOR.

JAMES A. M: INTOSH FIG.6 WWZWMMW ATTORNEYS United States Patent 3,286,866 PLASTIC CAP James A. McIntosh, Upper Montclair, NJ., assignor to Mack-Wayne Plastics Company, Wayne, NJ., a corporation of New Jersey Filed Apr. 15, 1965, Ser. No. 448,495 4 Claims. (Cl. 215-40) My invention relates to an improvement in sealing closures for containers having threaded necks.

Recent developments in the art of linerless sealing closures for containers having threaded necks, especially linerless sealing closures made from polypropylene, provide resilient annular sleeves, depending downwardly and outwardly and/or inwardly from the inner top wall of the sealing closures, for contact with the upper rim of the threaded neck container in order to effect a tight seal. Such linerless sealing closures have in general proven unsatisfactory due to the fact that the threaded neck containers which they are designed to seal are fabricated from glass and plastics such as polyethylene and polypropylene and these blown or molded containers are notorious for their uneven upper rim surfaces. Hence there is a need in the art for a linerless sealing closure which has suflicient flexibility to. seal tightly such containers and which can withstand repeated sealings without deformation. My invention satisfies such a need by providing a sealing closure having two concentric resilient annular members depending downwardly and outwardly from the inner top wall of the sealing closure, the innermost resilient member being larger than the other such that in sealing position the innermost resilient member is deflected and pressed by the neck rim against the outer most resilient member to effect a tight seal even with uneven neck rim surfaces.

More particularly, my invention provides a closure for use on a container having a threaded neck which neck includes a threaded outer wall, an inner wall and an interconnecting rim. The closure member itself has a top wall and depending therefrom is a tapped cylindrical skirt which threadedly engages the threaded outer wall of the neck. An annular resilient bead is positioned on the under side of the top wall concentrically within the threaded skirt. The annular resilient bead is sized so that its median diameter is greater than the diameter of the inner wall of the neck but less than the diameter of the outer wall of the neck. The closure member is also provided with an annular resilient sleeve positioned on the under side of the top wall within the annular resilient head, the sleeve being joined or sealed at its inner peripheral edge to the top wall and depending angularly downwardly from the top wall and outwardly toward the skirt. The sleeve is generally in the form of a hollow, truncated cone tapering outwardly from its attachment to the top wall. The slant height of the sleeve from its inner peripheral edge to its outer peripheral edge is greater than the radial distance between the inner peripheral edge and the head.

When the closure member engages the threaded neck of the container and advances downwardly to a sealed position, the resilient sleeve is deflected upwardly and outwardly so that the resilient sleeve bears against the resilient annular bead. In effect the sleeve is then supported at its inner peripheral edge by its attachment to the top wall and is supported at a second point, generally close to its outer peripheral edge, by the resilient annular bead, while the rim of the neck is maintained in contact with the resilient sleeve generally intermediate the points of support, thereby creating an extremely effective sealing relationship.

The closure of my invention can be fabricated from a variety of materials and in several different manners.

3,286,866 Patented Nov. 22, 1966 The top wall and cylindrical skirt can be made of any material possessing the required strength and rigidity, e.g. any of the more common metals or the more rigid plastics. The bead and sleeve can be formed from any of the well known resilient plastic materials. The material employed in the resilient sleeve, however, must not be so flexible that the rotation of the rim when brought into contact with the resilient sleeve in sealing relationship will cause the sleeve to become twisted. The top well including the skirt of my closure can be fabricated as a unit such as by casting or machining and the prefabricated resilient annular bead and sleeve sealed in place within the skirt. Preferably, the entire closure, includ ing top wall, skirt, annular resilient bead and resilient sleeve, is molded as a unit employing a semi-flexible, semirigid plastic such as polypropylene.

Advantageously, the resilient sleeve is formed tapering outwardly from its inner peripheral edge to its outer peripheral edge. Such shape provides the sleeve with a greater degree of rigidity at its point of attachment to the top wall and a greater degree of flexibility at its point of contact with the rim. Also, the resilient annular head is formed tapering outwardly from its attachment to the top wall. Thus both the resilient sleeve and bead can have a wall thickness, for example, varying from 10 to 30 thousandths of an inch. The resilient annular sleeve is positioned such that its inner surface is at an angle with respect to the top wall surface of 40 to 50 and its outer surface is at an angle of 55 to 65 and the resilient annular head is positioned such that its inner surface is at an angle with respect to the top wall surface of to and its outer surface is at an angle of 80 to In order to describe my invention with greater detail reference is made to the attached drawing illustrative of a particularly advantageous embodiment of my invention in which FIGURE 1 is a plan view of a closure member;

FIGURE 2 is a sectional view taken along the line 22 of FIGURE 1 showing the closure member prior to engaging the neck of a container;

FIGURE 3 is a sectional view similar to FIGURE 2 showing the container neck in sealing relationship with the closure member;

FIGURE 4 is a plan section taken along the line 44 of FIGURE 3;

FIGURE 5 is a fragmentary sectional view taken along the line 55 of FIGURE 3;

FIGURE 6 is a developed surface taken along the outside periphery of the container neck showing the sealing relationship.

In the drawing the reference numeral 10 indicates the closure member and the reference numeral 12 indicates the threaded neck of a container. The neck 12 includes a threaded outer wall 14 having threads 15, an inner wall 16 and an interconnecting rim 18 at the upper ends of the outer wall 14 and the inner wall 16. As shown in the drawing, rim 18 has an uneven upper rim surface with a depression 19. The closure member 10 has a top wall 20 and an internally tapped generally cylindrical skirt 22 extending downwardly from the top wall 20. While the upper surface of top wall 20 is illustrated in the shape of a concave dish, the portion of the lower surface 21 within skirt 22 is substantially planar. The cylindrical skirt 22 is tapped to provide threads 23 which mate with the threads 15 on the neck 12. An annular resilient bead 24 is positioned on the lower surface 21 of top wall 20 projecting downwardly and disposed concentrically within the cylindrical skirt 22. An annular resilient sleeve 26 is also positioned on the lower surface 21 of top wall 20 projecting downwardly and outwardly and disposed concentrically within the annular resilient bead 24. The inner peripheral edge 30 of the annular sleeve 26 is substantially parallel to the outer peripheral edge 28 so that the resilient annular sleeve 26 is generally in the form of a hollow truncated cone. 26 is tapered from its outer peripheral edge 28 to its inner peripheral edge 30. The relative dimensions of the various components of closure member 10are critical. Thus, the median diameter of resilient annular bead 24 is greater than the diameter of the inner wall 16 of neck 12 but less than the diameter of the outer wall 14 of neck 12. Furthermore, the slant height of annular sleeve 26, i.e. the linear radial dimension from its outer peripheral edge 28 to its inner peripheral edge 30 is greater than the radial distance between the inner peripheral edge 30 and median diameter of resilient annular bead 24. The necessity of these relative dimensions will become evident from the discussion below. Advantageously, the diameter of resilient annular sleeve 26 at its inner peripheral edge 30 is less than the diameter of the inner wall 16 of neck 12;

In operation the closure member 10 is placed upon the neck 12 and as the threads 15 on the outer wall 14 of the neck 12 engage the threads 23 on the cylindrical skirt 22, the outer peripheral edge 28 of annular sleeve 26 fits within the inner wall 16 of neck 12 and the rim 18 of neck 12 eventually bears against the lower surface of the annular sleeve 26. This relationship between closure member 10 and neck 12 is illustrated in FIGURE 2.

FIGURE 3 illustrates the relationship existing between closure member 10 and neck 12 when neck 12 is completely engaged by closure member 10 and a sealing relationship is established. To provide the sealing relationship, the annular resilient sleeve 26 has been displaced upwardly and outwardly by rim 18 so that rim 18 now bears against the lower surface of resilient annular sleeve 26 while the resilient annular bead 24 bears against the upper surface of annular sleeve 26. In this juxtaposition the annular resilient sleeve 26 is compressed between the lower outer surface of resilient annular bead 24 and rim 18 proximate the mid-point of rim 18 of neck 12. Furthermore, in this juxtaposition the annular resilient bead 24 is compressed by the upper inner surface. of resilient annular sleeve 26 only to the extent that the annular resilient sleeve 26 is compressed by rim 18. Hence where is a depression 19 in the upper surface of rim 18, the resiliency of annular head 24 will maintain pressure of resilient annular sleeve 26 against rim 18 thereby establishing a sealing relationship .as shown in detail in FIGURES and 6.

The diameter of the peripheral edge 30 of annular sleeve 26 need not be less than the diameter of the inner wall 16 but can be equal to or somewhat greater than the diameter of inner wall 16 depending on the thickness ofthe neck wall. In such instance the rim 18 initially will bear against the outer peripheral edge 28 and, as the closure member is advanced downwardly relative to the neck 12, the resilient sleeve 26 will be displaced upwardly and inwardly due to its angular disposition so that eventually the rim 18 will bear against the lower surface of sleeve 26 while bead 24 will bear against the upper surface of sleeve 26.

From the above discussion it will be obvious that while the diameter of the inner peripheral edge 30 may or may not be less than the diameter of the inner wall 16, it is essential that the slant height of resilient sleeve 26. be greater than the radial distance between the inner pe- The annular resilient sleeve.

4. ripheral edge 30 and the median diameter of annular bead 24 so that when the resilient sleeve 26 is displaced by the rim 18, the sleeve is of such size that it will reach to at least the median diameter of annular bead 24.

I claim:

1. A closure for use on a threaded neck container including a threaded outer wall, an inner wall and an interconnecting rim, said,closure comprising a top wall, a tapped cylindrical ski-rt depending from the top wall for threaded engagement with the-outer wall of the neck, an annular resilient bead positioned on the under side of the top wall tapering outwardly from its inner peripheral edge to its outer peripheral edge with its inner surface at an angle with respect to the top wall surf-ace of to and its outer surface at an angle with respect to the top wall of 80 to the annular resilient bead being, disposed concentrically with the skirt and having a median diameter greater than the diameter of the inner wall of the neck but less than the diameter of the outer wall of the neck, an annular resilient sleeve positioned on the under side of the top wall and disposed concentrically within the annular resilient head, the annular resilient sleeve being joined at its inner peripheral edge to the top wall, depending :angularly downwardly from the top wall outwardly toward the skirt such that its inner surface is at an angle with respect to the top wall surface of 40 to 50 and its outer surface is at an angle with respect to the top wall surface of 55 to 65, and having a slant height from its inner peripheral edge to its outer peripheral edge greater than the radial distance between the inner peripheral edge and the median diameter of the annular resilient bead; whereby as the closure engages the threaded neck, the resilient sleeve is deflected upwardly and outwardly by. the rim so as to bear against the annular resilient bead on one side whereby the outer peripheral edge of the annular resilient head is deflected upwardly and outwardly by the deflected'resilient sleeve and against the rim on the other side thereby forming a sealing relationship.

2. The closure of claim 1 in which the diameter of the inner peripheral edge of the annular resilient sleeve is less than the diameter of the inner wall of the neck.

3. The closure of claim 1 inwhich the annular resilient bead has a wall thickness varying from 10 to 30 thousandths of an inch.

4. The closure of claim 1 .in which the annular resilient sleeve is formed tapering outwardly from its inner peripheral edge to its outer peripheral edge.

References Cited by the Examiner UNITED STATES PATENTS 3,053,406 9/ 1962 Wandell 215-41 3,055,526 9/1962 Plunkett 21543 X 3,203,571 8/1965 Plunkett 215-40 FOREIGN PATENTS 1,213,812 11/1959 France.

OTHER REFERENCES German printed application 1,107,541, May 1961.

JOSEPH R. LECLAIR, Primary Examiner.

D. F. NORTON, Assistant Examiner. 

1. A L CLOSURE FOR USE ON A THREADED NECK CONTAINER INCLUDING A THREADED OUTER WALL, AN INNER WALL AND AN INTERCONNECTING RIM, SAID CLOSURE COMPRISING A TOP WALL, A TAPPED CYLINDRICAL SKIRT DEPENDING FROM THE TOP WALL FOR THREADED ENGAGEMENT WITH THE OUTER WALL OF THE NECK, AN ANNULAR RESILIENT BEAD POSITIONED ON THE UNDER SIDE OF THE TOP WALL TAPERING OUTWARDLY FROM ITS INNER PERIPHERAL EDGE TO ITS OUTER PERIPHERAL EDGE WITH ITS INNER SURFACE AT AN ANGLE WITH RESPECT TO THE TOP WALL SURFACE OF 75* TO 85* AND ITS OUTER SURFACE AT AN ANGLE WITH RESPECT TO THE TOP WALL OF 80* TO 90*, THE ANNULAR RESILIENT BEAD BEING DISPOSED CONCENTRICALLY WITH THE SKIRT AND HAVING A MEDIAN DIAMETER GREATER THAN THE DIAMETER OF THE INNER WALL OF THE NECK BUT LESS THAN THE DIAMETER OF THE OUTER WALL OF THE NECK, AN ANNULAR RESILIENT SLEEVE POSITIONED ON THE UNDER SIDE OF THE TOP WALL AND DISPOSED CONCENTRICALLY WITHIN THE ANNULAR RESILIENT BEAD, THE ANNULAR RESILIENT SLEEVE BEING JOINED AT ITS INNER PERIPHERAL EDGE TO THE TOP WALL, DEPENDING ANGULARLY DOWNWARDLY FROM THE TOP WALL OUTWARDLY TOWARD THE SKIRT SUCH THAT ITS INNER SURFACE IS AT AN ANGLE WITH RESPECT TO THE TOP WALL SURFACE OF 40* TO 50* AND ITS OUTER SURFACE IS AT AN ANGLE WITH RESPECT TO THE TOP WALL SURFACE OF 55* TO 65*, AND HAVING A SLANT HEIGHT FROM ITS INNER PERIPHERAL EDGE TO ITS OUTER PERIPHERAL EDGE GREATER THAN THE RADIAL DISTANCE BETWEEN THE INNER PERIPHERAL EDGE AND THE MEDIAN DIAMETER OF THE ANNULAR RESILIENT BEAD; WHEREBY AS THE CLOSURE ENGAGES THE THREADED NECK, THE RESILIENT SLEVE IS DEFLECTED UPWARDLY AND OUTWARDLY BY THE RIM SO AT TO BEAR AGAINST THE ANNULAR RESILIENT BEAD ON ONE SIDE WHEREBY THE OUTER PERIPHERAL EDGE OF THE ANNULAR RESILIENT BEAD IS DEFLECTED UPWARDLY AND DOWNWARDLY BY THE DEFLECTED RESILIENT SLEEVE AND AGAINST THE RRIM ON THE OTHER SIDE THEREBY FORMING A SEALING RELATIONSHIP. 